100,000 Mile Tuneup

scrowetn · November 9, 2005

Well my 1999 GMC Sierra SLT Z85 that I purchased new in November of 1998 just rolled past 100,000 miles. I used this forum to research the best spark plugs and ended up going with the AC Delco 41-985 Iridium plugs (thanks guys). They were 7$ each (BIG OUCH) at my local Advance Auto. O'Reilly's had them for $6 each but they had to be ordered. If I could have waited a few more days, EconomyAuto on Ebay had a complete set of 8 for $20 plus $5 shipping ($25 vs $61 w/tax). I was really surprised when I pulled the old 41-952 platinum plugs and they were all still in great shape with exact .060 gaps and no fouling. I probably could have gotten another 50,000 miles out of them. Except for the passenger side rear plug, all plugs were really easy to get to. Twisting and then pulling the boots off the old plugs was a great tip I read on this forum (thanks again). I used Permatex anti-seize lub on the threads and a generous coating of dieletic grease inside the wire boots when I installed the new plugs. All of the spark plug wires were in good shape so I didn't bother replacing them.

Here's a run down of the problems I've had with my Sierra over the past 7 years:

Sliding Rear Window Leaks - Dealer replaced the window 3 times under warranty and it still leaked! They also replaced the wrong window (passenger rear side window) twice After the truck went out of warranty, I had a local glass shop replace it with a better OEM model ($285) and it's never leaked since.

Battery Side Post Broke Off - Dealer replaced the batter under warranty. I had to take it back and make them replace the rusting battery tray that had it's paint eaten off by the leaking battery acid.

Service 4WD Warning Msg - Big thanks again to this forum for the advice on repairing/replacing the 4WD switch. I pulled it and sent it to ModuleMaster who repaired it for only $15. Works great now!

Emergency Brakes Not Working - I pulled the rear rotors and found that the driver side brake shoe and rotor were badly worn. I believe a plastic grocery bag had some how gotten wrapped around the rear axle and caused the driver side emergency brake to stick closed. I replaced the driver side rotor, installed new emergency brake shoes and new rear brake pads. On my truck, only the driver's side emergency brake plunger had an adjustment nut. On the passenger side I had to take the shoes off each time I wanted to adjust them out. I measured the driver's side adjustment and used that to start adjusting the passenger side. Believe it or not, the rear brake pads still had over 25% life on them and the fronts over 50% life after 95,000 miles. I used Bendix metalic brake pads on the rear and didn't bother changing the front. TIP: If the single small bolt that holds the emergency brake shoes on breaks off (happened to me twice) you can remove one of the lug studs and get to it with a long EZout. I ended up drilling and retapping mine for a stronger bolt.

ABS Brakes - I've had the premature ABS activation problem for quite awhile now although it only seems to happen when I'm exiting the interstate on a downhill grade. I do not live in a "rust state" so I can't take advantage of the recent recall but I did go ahead and file a complaint with the NHTSA via their website. I advise everyone else to do the same and maybe they will expand the scope of the recall. Recently, my brake and ABS lights started coming on after about 5 - 10 minutes of driving, seems to happen when I hit a small bump or something in the road. Other than taking the truck back to the dealer, where can I go and have the ABS codes read? None of the local parts stores (Advance, O'Reilly, Pep Boys, etc) can read the ABS codes (only engine codes).

Sorry I ran on for so long, but thanks again for all the great information everyone contributes to this forum!!! I wish I'd found this forum years ago.